1. Field of the Invention
The present invention relates to a process for correction of control parameters of an internal combustion engine of a motor vehicle in order to eliminate the potential phenomena known as torque jolts that can occur during particular vehicle operating conditions.
2. Discussion of the Background
It is known that, under certain operating conditions of a motor vehicle equipped with an internal combustion engine, especially in transition phases (such as hard acceleration, etc.), there occur phenomena of oscillations of the torque transmitted to the vehicle wheels, or in other words jolts, these jolts then affecting the comfort of the vehicle passengers.
These oscillations originate mainly from the kinematic chain connecting the engine to the tire/road interface. In fact, the mechanical energy at the end of the crankshaft is transmitted to the wheels by a transmission system which traditionally comprises a clutch, a gearbox and a differential, each of these elements having its own damping and stiffness. As a result, any abrupt variation of the engine torque in the crankshaft region is transmitted to the wheels as oscillations whose amplitude will depend on the characteristics of the transmission system.
Numerous methods for remedying these torque oscillations have been conceived. Thus it is known from the prior art, especially from European Patent Application EP A 461504 and World Patent Application WO A 90/06441, that the torque of an engine can be regulated in such a way as to reduce or suppress the sensation of torque oscillations experienced by the vehicle operator.
According to this known prior art, the engine control parameters, or in other words the injection time or the ignition advance, are corrected to eliminate the oscillations by performing monitoring of the engine torque at the wheels and by correcting in the control loop the value of the chosen control parameter or parameters as a function of the amplitude of the detected oscillations.
Such methods nevertheless suffer from certain disadvantages, especially that of causing increased pollutant emission, since the main object of the corrections made is to reduce the engine torque by lowering combustion quality.
In addition, the known methods are limited to correcting the consequences of an abrupt torque variation after its occurrence has been recorded and identified, without acting on the cause thereof, or in other words abrupt variation of the air flow.